Many trials to produce a pleasant interior space have been made by suppressing a temperature rise in the interior space, with a heat radiation energy of sun light flowing into the interior space via a window glass reduced, by suppressing a consumption of an electrical energy consumed through a drive of a cooling device, and by maintaining a high visible light transmittance of the window glass.
A patent document 1 describes that it has been proposed that the laminated glass having a resin interlayer film interposed between at least two sheets of transparent glass plate-like body, electrically conductive ultra-fine particles, each of the ultra-fine particles having a particle diameter up to 0.2 μm, are dispersed in the interlayer film so that the laminated glass having a solar transmittance which can be reduced to about 50% while the transmittance in a visible light area is highly maintained can be achieved.
It should, however, be noted that, since the laminated glass disclosed in patent document 1 serves to absorb light in the infrared area, the laminated glass itself becomes warm to increase the temperature, and radiant rays directed from the laminated glass to the interior space called a re-radiation for the radiation against sun light rays are radiated, the temperature in the interior space is raised after a lapse of a long time.
A patent document 2 discloses an infrared ray reflective film which is a lamination of dielectrics having different indexes of refractions, as the infrared ray reflective film which reflects the infrared ray without use of the electrically conductive film. In addition, each of patent documents 3 and 4 discloses the infrared ray reflective film which is a lamination of resin films having different indexes of refractions.
It is known as the laminated glass having a heat ray reflection function that the laminated glass is prepared using a three-layer structure intermediate film in which the transparent plastic film on which the infrared reflective film is formed is inserted between the two sheets of resin intermediate film.
Ordinarily, the laminated glass is processed at a high temperature and under a high pressure using an autoclave. Thus, the glass plate and three-layer structure intermediate film are heat molten to each other by means of the resin intermediate film.
For example, a patent document 5 discloses the laminated glass in which a flexible lamination body in which a heat-ray reflective plastic film formed by a thin film on a polyester film is sandwiched between two sheets of resin intermediate film is inserted between two sheets of glass plate to be laminated.
In addition, patent document 4 discloses an infrared ray shielding film constituted by a multiple number of plastic layers and sandwiched between two sheets of polyvinyl butyral sheet, this infrared ray shielding film being sandwiched between two sheets of glass plate. Patent document 4 also describes that this infrared ray shielding film has the shrinkage of 2% or smaller under a process of 150° C. and for 30 minutes in both of a film formation direction thereof and in a width direction thereof, from a viewpoint of preventing an occurrence of cracks and a peeling off between the glass and the film after an adherence of the glass plates on the infra-red ray shielding film, and has a shrinkage difference of 0.5% or smaller under the process of 150° C. and for 30 minutes, from the viewpoint of preventing a wrinkle generation.
Furthermore, a patent document 6 describes that a functional film having a selective light transmittance and an electrical conductivity is sandwiched between polyvinyl butyral (PVB) films to form the laminated glass, in order to prevent a defect such as a wrinkle when a polyethylene terephthalate film is sandwiched between two sheets of PVB film and is laminated to form the laminated glass and, in order to prevent an outer appearance default such as a wrinkle, a thermal expansion rate of a polyester terephthalate used for the functional film is 0.1 through 1.0% in one direction, and the thermal shrinkage of the polyester terephthalate in an orthogonal direction to the one direction is 0.1 through 1.0%. A patent document 7 describes that an infrared ray reflective film in which a film of oxide indium or silver is formed on a plastic film is used and the infrared ray reflective film having the thermal shrinkage of the plastic film during a thermal process of the plastic film of 1 through 20% when preparing the laminated glass.
As a film to reflect the infrared ray, patent documents 8 and 9 describe the infrared ray reflective films including resin multi-layer films.